Pigments comprising alumina hydrate and a dye, and polymer composites formed thereof

Abstract

A composite material includes a polymer matrix and a pigment dispersed in the polymer matrix. The pigment includes an alumina hydrate particulate material and a dye. The dye is covalently bonded to a surface of the alumina hydrate particulate material.

What is claimed is: 
     
       1. A pigment comprising an alumina hydrate particulate material and a dye, the dye being directly covalently bonded to an oxygen atom on the surface of the alumina hydrate particulate material. 
     
     
       2. The pigment of  claim 1 , wherein the alumina hydrate particulate material has a general composition of Al(OH) a O b , where 0<a≦3 and b=(3−a)/2. 
     
     
       3. The pigment of  claim 2 , wherein the alumina hydrate particulate material comprises 1% to 38% water content by weight. 
     
     
       4. The pigment of  claim 1 , wherein the alumina hydrate particulate material has a longest dimension not greater than about 1000 nm. 
     
     
       5. The pigment of  claim 1 , wherein the alumina hydrate particulate material has an aspect ratio of at least about 2:1. 
     
     
       6. The pigment of  claim 1 , wherein the dye is selected from the group consisting of anthracene dyes, azo dyes, acridine dyes, azine dyes, oxazine dyes, thiazine dyes, quinoline dyes, polymethine dyes, hydrazone dyes, triazine dyes, porphyrin dyes, porphyrazine dyes, sulfur dyes, quinacridone dyes, formazane dyes, nitro dyes, nitroso dyes, azomethine dyes, and polyol dyes.